There is a growing need to improve the energy absorption properties of automotive interior trim substrates which also provide structural support to the sheet metal structure of a vehicle. Such sheet metal structures include pillars, side rails, and roof structures. However, the industry has been challenged in determining a cost effective way of manufacturing interior trim substrates and interior components in order to meet industry demands. For example, manufacturers continue to search for ways of improving the properties of substrates for absorbing energy in a cost effective manner while providing structural support.
One challenge that manufacturers are faced with is that energy absorption throughout the passenger compartment, such as on pillars, side rails, or the roof structure of a vehicle, requires different amounts or different densities of energy absorption material, including molded foam or beads. This is due to the vehicle structure design which typically includes a plurality of sheet metal pieces that form the passenger compartment of a vehicle. The thickness and geometric stiffness of the sheet metal typically determine the amount of energy absorption material required. That is, the thicker and/or stiffer the sheet metals is, the more absorption material is required to meet industry demands. Thus, materials of different amounts of energy absorption and/or different densities would be useful to have in interior trim substrates.
Although current energy absorbing parts may be adequate, improvements can be made thereupon. Currently, multi-density component parts are manufactured for energy absorbing purposes. Some multi-density component parts are separately manufactured and then combined to comprise an energy absorbing part which is fastened to an area of a vehicle compartment, such as a pillar. More specifically, single density foam or beads are molded to form a shape of a vehicle component. The molded foam or beads are then attached to a predetermined area on an interior trim material or a shell which then fastens onto the structure of a vehicle. The separate manufacturing processes used in forming the molded foam or beads and the interior trim substrates result in additional manufacturing time and costs.
U.S. Pat. No. 5,700,050 to Gonas discloses an energy absorbing interior automotive trim part. The part has a shell made from polypropylene sections is divided via partitions to extend from the outer wall of the shell. The shell is then filled with structurally engineered energy absorbing foam.
Thus, what is needed is an improved system and method of making an integrally formed substrate that more efficiently meets the industry demands for energy absorption on collision impacts.